From e8fdec6378a4a25e501bd9d2aae756a629910ebd Mon Sep 17 00:00:00 2001
From: rwiktorek <rafalwiktorek71@gmail.com>
Date: Tue, 5 May 2020 00:35:38 +0200
Subject: [PATCH 1/4] full solution TODO: add unit tests

---
 BDD/BerlinClockFeatureSteps.cs         | 13 +++---
 BerlinClock.csproj                     | 16 ++++++-
 Builders/BerlinClockEntityBuilder.cs   | 42 ++++++++++++++++++
 Builders/BerlinClockRowsBuilderBase.cs | 59 ++++++++++++++++++++++++++
 Builders/HourRowsBuilder.cs            | 31 ++++++++++++++
 Builders/MinuteRowsBuilder.cs          | 42 ++++++++++++++++++
 Classes/ITimeConverter.cs              | 12 ------
 Classes/TimeConverter.cs               | 15 -------
 Converters/TimeConverter.cs            | 34 +++++++++++++++
 Extensions/IntExtensions.cs            |  7 +++
 Extensions/StringExtensions.cs         | 16 +++++++
 Models/BerlinClockEntity.cs            | 20 +++++++++
 Models/BerlinClockRendererRequest.cs   | 12 ++++++
 Models/BerlinClockRows.cs              |  8 ++++
 Models/Time.cs                         | 15 +++++++
 Parsers/TimeParser.cs                  | 26 ++++++++++++
 Renderers/BerlinClockRowRenderer.cs    | 26 ++++++++++++
 17 files changed, 358 insertions(+), 36 deletions(-)
 create mode 100644 Builders/BerlinClockEntityBuilder.cs
 create mode 100644 Builders/BerlinClockRowsBuilderBase.cs
 create mode 100644 Builders/HourRowsBuilder.cs
 create mode 100644 Builders/MinuteRowsBuilder.cs
 delete mode 100644 Classes/ITimeConverter.cs
 delete mode 100644 Classes/TimeConverter.cs
 create mode 100644 Converters/TimeConverter.cs
 create mode 100644 Extensions/IntExtensions.cs
 create mode 100644 Extensions/StringExtensions.cs
 create mode 100644 Models/BerlinClockEntity.cs
 create mode 100644 Models/BerlinClockRendererRequest.cs
 create mode 100644 Models/BerlinClockRows.cs
 create mode 100644 Models/Time.cs
 create mode 100644 Parsers/TimeParser.cs
 create mode 100644 Renderers/BerlinClockRowRenderer.cs

diff --git a/BDD/BerlinClockFeatureSteps.cs b/BDD/BerlinClockFeatureSteps.cs
index 4390f3cb..f8cd7bf1 100644
--- a/BDD/BerlinClockFeatureSteps.cs
+++ b/BDD/BerlinClockFeatureSteps.cs
@@ -1,27 +1,26 @@
-using System;
-using TechTalk.SpecFlow;
+using TechTalk.SpecFlow;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using System.Linq;
+using BerlinClock.Converters;
 
 namespace BerlinClock
 {
     [Binding]
     public class TheBerlinClockSteps
     {
-        private ITimeConverter berlinClock = new TimeConverter();
-        private String theTime;
+        private readonly ITimeConverter _berlinClock = new TimeConverter();
+        private string _theTime;
 
         
         [When(@"the time is ""(.*)""")]
         public void WhenTheTimeIs(string time)
         {
-            theTime = time;
+            _theTime = time;
         }
         
         [Then(@"the clock should look like")]
         public void ThenTheClockShouldLookLike(string theExpectedBerlinClockOutput)
         {
-            Assert.AreEqual(berlinClock.convertTime(theTime), theExpectedBerlinClockOutput);
+            Assert.AreEqual(_berlinClock.ConvertTime(_theTime), theExpectedBerlinClockOutput);
         }
 
     }
diff --git a/BerlinClock.csproj b/BerlinClock.csproj
index ac8af99d..514b738f 100644
--- a/BerlinClock.csproj
+++ b/BerlinClock.csproj
@@ -50,14 +50,25 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="BDD\BerlinClockFeatureSteps.cs" />
+    <Compile Include="Builders\BerlinClockEntityBuilder.cs" />
+    <Compile Include="Builders\BerlinClockRowsBuilderBase.cs" />
+    <Compile Include="Builders\HourRowsBuilder.cs" />
+    <Compile Include="Builders\MinuteRowsBuilder.cs" />
+    <Compile Include="Extensions\IntExtensions.cs" />
+    <Compile Include="Extensions\StringExtensions.cs" />
+    <Compile Include="Models\BerlinClockEntity.cs" />
+    <Compile Include="Models\BerlinClockRendererRequest.cs" />
+    <Compile Include="Models\BerlinClockRows.cs" />
+    <Compile Include="Models\Time.cs" />
+    <Compile Include="Parsers\TimeParser.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="BDD\BerlinClockFeatureSteps.feature.cs">
       <AutoGen>True</AutoGen>
       <DesignTime>True</DesignTime>
       <DependentUpon>BerlinClockFeatureSteps.feature</DependentUpon>
     </Compile>
-    <Compile Include="Classes\ITimeConverter.cs" />
-    <Compile Include="Classes\TimeConverter.cs" />
+    <Compile Include="Converters\TimeConverter.cs" />
+    <Compile Include="Renderers\BerlinClockRowRenderer.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="App.config" />
@@ -70,6 +81,7 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
+  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.
diff --git a/Builders/BerlinClockEntityBuilder.cs b/Builders/BerlinClockEntityBuilder.cs
new file mode 100644
index 00000000..7466dfc5
--- /dev/null
+++ b/Builders/BerlinClockEntityBuilder.cs
@@ -0,0 +1,42 @@
+using BerlinClock.Extensions;
+using BerlinClock.Models;
+
+namespace BerlinClock.Builders
+{
+    public interface IBerlinClockEntityBuilder
+    {
+        BerlinClockEntity Build(Time time);
+    }
+
+    public class BerlinClockEntityBuilder : IBerlinClockEntityBuilder
+    {
+        private readonly IHourRowsBuilder _hourRowsBuilder;
+        private readonly IMinuteRowsBuilder _minuteRowsBuilder;
+
+        public BerlinClockEntityBuilder() : this(new HourRowsBuilder(), new MinuteRowsBuilder())
+        {
+
+        }
+
+        public BerlinClockEntityBuilder(IHourRowsBuilder hourRowsBuilder, IMinuteRowsBuilder minuteRowsBuilder)
+        {
+            _hourRowsBuilder = hourRowsBuilder;
+            _minuteRowsBuilder = minuteRowsBuilder;
+        }
+
+        public BerlinClockEntity Build(Time time)
+        {
+            var hourRows = _hourRowsBuilder.Build(time);
+            var minuteRows = _minuteRowsBuilder.Build(time);
+
+            return new BerlinClockEntity
+            {
+                YellowLampSign = time.Second.IsEven() ? 'Y' : 'O',
+                FirstHoursRow = hourRows.FirstRow,
+                SecondHoursRow = hourRows.SecondRow,
+                FirstMinutesRow = minuteRows.FirstRow,
+                SecondMinutesRow = minuteRows.SecondRow
+            };
+        }
+    }
+}
diff --git a/Builders/BerlinClockRowsBuilderBase.cs b/Builders/BerlinClockRowsBuilderBase.cs
new file mode 100644
index 00000000..11e8a63e
--- /dev/null
+++ b/Builders/BerlinClockRowsBuilderBase.cs
@@ -0,0 +1,59 @@
+using BerlinClock.Models;
+using BerlinClock.Renderers;
+using System;
+
+namespace BerlinClock.Builders
+{
+    public interface IBerlinClockRowsBuilder
+    {
+        BerlinClockRows Build(Time time);
+    }
+
+    public abstract class BerlinClockRowsBuilderBase : IBerlinClockRowsBuilder
+    {
+        protected abstract int FirstRowLampsAmount { get; }
+        protected abstract int FirstRowLampsValue { get; }
+        protected abstract int SecondRowLampsAmount { get; }
+        protected abstract int SecondRowLampsValue { get; }
+        protected abstract char TurnedOnLampSign { get; }
+        protected virtual Func<string, string> FirstRowAdditionalFormatting { get; }
+        protected virtual Func<string, string> SecondRowAdditionalFormatting { get; }
+
+        private readonly IBerlinClockRowRenderer _berlinClockRowRenderer;
+
+        public BerlinClockRowsBuilderBase(IBerlinClockRowRenderer berlinClockRowRenderer)
+        {
+            _berlinClockRowRenderer = berlinClockRowRenderer;
+        }
+
+        public BerlinClockRows Build(Time time)
+        {
+            var timePart = ExtractTimePart(time);
+            var amountOfTurnedOnLampsAtFirstRow = (int)timePart / FirstRowLampsValue;
+            var amountOfTurnedOffLampsAtFirstRow = FirstRowLampsAmount - amountOfTurnedOnLampsAtFirstRow;
+
+            var amountOfTurnedOnLampsAtSecondRow = (int)(timePart - amountOfTurnedOnLampsAtFirstRow * FirstRowLampsValue) / SecondRowLampsValue;
+            var amountOfTurnedOffLampsAtSecondRow = SecondRowLampsAmount - amountOfTurnedOnLampsAtSecondRow;
+
+            return new BerlinClockRows
+            {
+                FirstRow = _berlinClockRowRenderer.Render(new BerlinClockRendererRequest
+                {
+                    AmountOfTurnedOnLamps = amountOfTurnedOnLampsAtFirstRow,
+                    AmountOfTurnedOffLamps = amountOfTurnedOffLampsAtFirstRow,
+                    TurnedOnLampSign = TurnedOnLampSign,
+                    AdditionalFormatting = FirstRowAdditionalFormatting
+                }),
+                SecondRow = _berlinClockRowRenderer.Render(new BerlinClockRendererRequest
+                {
+                    AmountOfTurnedOnLamps = amountOfTurnedOnLampsAtSecondRow,
+                    AmountOfTurnedOffLamps = amountOfTurnedOffLampsAtSecondRow,
+                    TurnedOnLampSign = TurnedOnLampSign,
+                    AdditionalFormatting = SecondRowAdditionalFormatting
+                })
+            };
+        }
+
+        protected abstract int ExtractTimePart(Time time);
+    }
+}
diff --git a/Builders/HourRowsBuilder.cs b/Builders/HourRowsBuilder.cs
new file mode 100644
index 00000000..ec2fdeb1
--- /dev/null
+++ b/Builders/HourRowsBuilder.cs
@@ -0,0 +1,31 @@
+using BerlinClock.Models;
+using BerlinClock.Renderers;
+
+namespace BerlinClock.Builders
+{
+    public interface IHourRowsBuilder : IBerlinClockRowsBuilder
+    {
+
+    }
+
+    public class HourRowsBuilder : BerlinClockRowsBuilderBase, IHourRowsBuilder
+    {
+        public HourRowsBuilder() : this(new BerlinClockRowRenderer())
+        {
+
+        }
+        public HourRowsBuilder(IBerlinClockRowRenderer berlinClockRowRenderer) : base(berlinClockRowRenderer)
+        {
+        }
+
+        protected override char TurnedOnLampSign => 'R';
+        protected override int FirstRowLampsAmount => 4;
+        protected override int FirstRowLampsValue => 5;
+        protected override int SecondRowLampsAmount => 4;
+        protected override int SecondRowLampsValue => 1;
+        protected override int ExtractTimePart(Time time)
+        {
+            return time.Hour;
+        }
+    }
+}
diff --git a/Builders/MinuteRowsBuilder.cs b/Builders/MinuteRowsBuilder.cs
new file mode 100644
index 00000000..670874c7
--- /dev/null
+++ b/Builders/MinuteRowsBuilder.cs
@@ -0,0 +1,42 @@
+using BerlinClock.Extensions;
+using BerlinClock.Models;
+using BerlinClock.Renderers;
+using System;
+
+namespace BerlinClock.Builders
+{
+    public interface IMinuteRowsBuilder : IBerlinClockRowsBuilder
+    {
+
+    }
+
+    public class MinuteRowsBuilder : BerlinClockRowsBuilderBase, IMinuteRowsBuilder
+    {
+        private const char QuarterSign = 'R';
+
+        public MinuteRowsBuilder() : this(new BerlinClockRowRenderer())
+        {
+
+        }
+
+        public MinuteRowsBuilder(IBerlinClockRowRenderer berlinClockRowRenderer) : base(berlinClockRowRenderer)
+        {
+        }
+
+        protected override int FirstRowLampsAmount => 11;
+        protected override int FirstRowLampsValue => 5;
+        protected override int SecondRowLampsAmount => 4;
+        protected override int SecondRowLampsValue => 1;
+        protected override char TurnedOnLampSign => 'Y';
+        protected override int ExtractTimePart(Time time)
+        {
+            return time.Minute;
+        }
+
+        protected override Func<string, string> FirstRowAdditionalFormatting => (row) =>
+        {
+            var n = 3;
+            return row.ReplaceEveryNthOccurence(TurnedOnLampSign, QuarterSign, n);
+        };
+    }
+}
diff --git a/Classes/ITimeConverter.cs b/Classes/ITimeConverter.cs
deleted file mode 100644
index 1d9e4c27..00000000
--- a/Classes/ITimeConverter.cs
+++ /dev/null
@@ -1,12 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace BerlinClock
-{
-    public interface ITimeConverter
-    {
-        String convertTime(String aTime);
-    }
-}
diff --git a/Classes/TimeConverter.cs b/Classes/TimeConverter.cs
deleted file mode 100644
index dd5bf4e0..00000000
--- a/Classes/TimeConverter.cs
+++ /dev/null
@@ -1,15 +0,0 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-
-namespace BerlinClock
-{
-    public class TimeConverter : ITimeConverter
-    {
-        public string convertTime(string aTime)
-        {
-            throw new NotImplementedException();
-        }
-    }
-}
diff --git a/Converters/TimeConverter.cs b/Converters/TimeConverter.cs
new file mode 100644
index 00000000..cd5264fb
--- /dev/null
+++ b/Converters/TimeConverter.cs
@@ -0,0 +1,34 @@
+using BerlinClock.Builders;
+using BerlinClock.Parsers;
+
+namespace BerlinClock.Converters
+{
+    public interface ITimeConverter
+    {
+        string ConvertTime(string aTime);
+    }
+
+    public class TimeConverter : ITimeConverter
+    {
+        private readonly IBerlinClockEntityBuilder _berlinClockEntityBuilder;
+        private readonly ITimeParser _timeParser;
+
+        public TimeConverter() : this(new BerlinClockEntityBuilder(), new TimeParser())
+        {
+
+        }
+
+        public TimeConverter(IBerlinClockEntityBuilder berlinClockEntityBuilder, ITimeParser timeParser)
+        {
+            _berlinClockEntityBuilder = berlinClockEntityBuilder;
+            _timeParser = timeParser;
+        }
+
+        public string ConvertTime(string aTime)
+        {
+            var time = _timeParser.Parse(aTime);
+            var berlinClockEntity = _berlinClockEntityBuilder.Build(time);
+            return berlinClockEntity.ToString();
+        }
+    }
+}
diff --git a/Extensions/IntExtensions.cs b/Extensions/IntExtensions.cs
new file mode 100644
index 00000000..65411e57
--- /dev/null
+++ b/Extensions/IntExtensions.cs
@@ -0,0 +1,7 @@
+namespace BerlinClock.Extensions
+{
+    public static class IntExtensions
+    {
+        public static bool IsEven(this int value) => value % 2 == 0;
+    }
+}
diff --git a/Extensions/StringExtensions.cs b/Extensions/StringExtensions.cs
new file mode 100644
index 00000000..606a4334
--- /dev/null
+++ b/Extensions/StringExtensions.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Linq;
+
+namespace BerlinClock.Extensions
+{
+    public static class StringExtensions
+    {
+        public static string ReplaceEveryNthOccurence(this string value, char valueToReplace, char newValue, int n)
+        {
+            var chars = value.Select((val, index) => 
+                val == valueToReplace && (index + 1) % n == 0 ? newValue : val);
+
+            return new string(chars.ToArray());
+        }
+    }
+}
diff --git a/Models/BerlinClockEntity.cs b/Models/BerlinClockEntity.cs
new file mode 100644
index 00000000..a9d6e143
--- /dev/null
+++ b/Models/BerlinClockEntity.cs
@@ -0,0 +1,20 @@
+using System;
+
+namespace BerlinClock.Models
+{
+    public class BerlinClockEntity
+    {
+        public char YellowLampSign { get; set; }
+        public string FirstHoursRow { get; set; }
+        public string SecondHoursRow { get; set; }
+        public string FirstMinutesRow { get; set; }
+        public string SecondMinutesRow { get; set; }
+
+        public override string ToString()
+        {               
+            return string.Join(Environment.NewLine, YellowLampSign, 
+                FirstHoursRow, SecondHoursRow, 
+                FirstMinutesRow, SecondMinutesRow);
+        }
+    }
+}
diff --git a/Models/BerlinClockRendererRequest.cs b/Models/BerlinClockRendererRequest.cs
new file mode 100644
index 00000000..09b7a992
--- /dev/null
+++ b/Models/BerlinClockRendererRequest.cs
@@ -0,0 +1,12 @@
+using System;
+
+namespace BerlinClock.Models
+{
+    public class BerlinClockRendererRequest
+    {
+        public int AmountOfTurnedOnLamps { get; set; }
+        public int AmountOfTurnedOffLamps { get; set; }
+        public char TurnedOnLampSign { get; set; }
+        public Func<string, string> AdditionalFormatting { get; set; }
+    }
+}
diff --git a/Models/BerlinClockRows.cs b/Models/BerlinClockRows.cs
new file mode 100644
index 00000000..4bf6bd27
--- /dev/null
+++ b/Models/BerlinClockRows.cs
@@ -0,0 +1,8 @@
+namespace BerlinClock.Models
+{
+    public class BerlinClockRows
+    {
+        public string FirstRow { get; set; }
+        public string SecondRow { get; set; }
+    }
+}
diff --git a/Models/Time.cs b/Models/Time.cs
new file mode 100644
index 00000000..e5be78b1
--- /dev/null
+++ b/Models/Time.cs
@@ -0,0 +1,15 @@
+namespace BerlinClock.Models
+{
+    public struct Time
+    {
+        public Time(int hour, int minute, int second)
+        {
+            Hour = hour;
+            Minute = minute;
+            Second = second;
+        }
+        public int Hour { get; private set; }
+        public int Minute { get; private set; }
+        public int Second { get; private set; }
+    }
+}
diff --git a/Parsers/TimeParser.cs b/Parsers/TimeParser.cs
new file mode 100644
index 00000000..184cbd4a
--- /dev/null
+++ b/Parsers/TimeParser.cs
@@ -0,0 +1,26 @@
+using BerlinClock.Models;
+using System;
+
+namespace BerlinClock.Parsers
+{
+    public interface ITimeParser
+    {
+        Time Parse(string time);
+    }
+
+    public class TimeParser : ITimeParser
+    {
+        public Time Parse(string time)
+        {
+            var timeParts = time.Split(':');
+            if (timeParts.Length != 3)
+                throw new Exception("Wrong time format");
+
+            var hour = int.Parse(timeParts[0]);
+            var minute = int.Parse(timeParts[1]);
+            var second = int.Parse(timeParts[2]);
+
+            return new Time(hour, minute, second);
+        }
+    }
+}
diff --git a/Renderers/BerlinClockRowRenderer.cs b/Renderers/BerlinClockRowRenderer.cs
new file mode 100644
index 00000000..c01afd43
--- /dev/null
+++ b/Renderers/BerlinClockRowRenderer.cs
@@ -0,0 +1,26 @@
+using BerlinClock.Models;
+using System.Text;
+
+namespace BerlinClock.Renderers
+{
+    public interface IBerlinClockRowRenderer
+    {
+        string Render(BerlinClockRendererRequest request);
+    }
+
+    public class BerlinClockRowRenderer : IBerlinClockRowRenderer
+    {
+        private const char TurnedOffLampSign = 'O';
+
+        public string Render(BerlinClockRendererRequest request)
+        {
+            var stringBuilder = new StringBuilder();
+            stringBuilder.Append(request.TurnedOnLampSign, request.AmountOfTurnedOnLamps);
+            stringBuilder.Append(TurnedOffLampSign, request.AmountOfTurnedOffLamps);
+
+            var row = stringBuilder.ToString();
+            return request.AdditionalFormatting != null
+                ? request.AdditionalFormatting(row) : row;
+        }
+    }
+}

From b38fa0ba086a220334e68736b7ab11ea8a27442a Mon Sep 17 00:00:00 2001
From: rwiktorek <rafalwiktorek71@gmail.com>
Date: Tue, 5 May 2020 11:24:41 +0200
Subject: [PATCH 2/4] unit tests and few fixes

---
 BerlinClock.Tests/BerlinClock.Tests.csproj    | 86 +++++++++++++++++++
 .../Builders/YellowLampRowBuilderTests.cs     | 30 +++++++
 .../Extensions/IntExtensionsTests.cs          | 29 +++++++
 .../Extensions/StringExtensionsTests.cs       | 52 +++++++++++
 .../Parsers/TimeParserExtensions.cs           | 47 ++++++++++
 BerlinClock.Tests/Properties/AssemblyInfo.cs  | 20 +++++
 .../Renderers/BerlinClockRowRendererTests.cs  | 79 +++++++++++++++++
 BerlinClock.Tests/packages.config             |  5 ++
 BerlinClock.csproj                            |  1 +
 BerlinClock.sln                               |  6 ++
 Builders/BerlinClockEntityBuilder.cs          | 14 +--
 Builders/BerlinClockRowsBuilderBase.cs        | 12 ++-
 Builders/HourRowsBuilder.cs                   |  4 +-
 Builders/MinuteRowsBuilder.cs                 |  4 +-
 Builders/YellowLampRowBuilder.cs              | 23 +++++
 Extensions/StringExtensions.cs                |  3 +
 Models/BerlinClockEntity.cs                   |  4 +-
 Parsers/TimeParser.cs                         |  6 +-
 Renderers/BerlinClockRowRenderer.cs           |  4 +
 19 files changed, 410 insertions(+), 19 deletions(-)
 create mode 100644 BerlinClock.Tests/BerlinClock.Tests.csproj
 create mode 100644 BerlinClock.Tests/Builders/YellowLampRowBuilderTests.cs
 create mode 100644 BerlinClock.Tests/Extensions/IntExtensionsTests.cs
 create mode 100644 BerlinClock.Tests/Extensions/StringExtensionsTests.cs
 create mode 100644 BerlinClock.Tests/Parsers/TimeParserExtensions.cs
 create mode 100644 BerlinClock.Tests/Properties/AssemblyInfo.cs
 create mode 100644 BerlinClock.Tests/Renderers/BerlinClockRowRendererTests.cs
 create mode 100644 BerlinClock.Tests/packages.config
 create mode 100644 Builders/YellowLampRowBuilder.cs

diff --git a/BerlinClock.Tests/BerlinClock.Tests.csproj b/BerlinClock.Tests/BerlinClock.Tests.csproj
new file mode 100644
index 00000000..8e547829
--- /dev/null
+++ b/BerlinClock.Tests/BerlinClock.Tests.csproj
@@ -0,0 +1,86 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props" Condition="Exists('..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props')" />
+  <Import Project="..\packages\NUnit.3.12.0\build\NUnit.props" Condition="Exists('..\packages\NUnit.3.12.0\build\NUnit.props')" />
+  <Import Project="..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props" Condition="Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props')" />
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{74F9D721-6839-4776-97C9-718145CED3D0}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <AppDesignerFolder>Properties</AppDesignerFolder>
+    <RootNamespace>BerlinClock.Tests</RootNamespace>
+    <AssemblyName>BerlinClock.Tests</AssemblyName>
+    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <ProjectTypeGuids>{3AC096D0-A1C2-E12C-1390-A8335801FDAB};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}</ProjectTypeGuids>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">15.0</VisualStudioVersion>
+    <VSToolsPath Condition="'$(VSToolsPath)' == ''">$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v$(VisualStudioVersion)</VSToolsPath>
+    <ReferencePath>$(ProgramFiles)\Common Files\microsoft shared\VSTT\$(VisualStudioVersion)\UITestExtensionPackages</ReferencePath>
+    <IsCodedUITest>False</IsCodedUITest>
+    <TestProjectType>UnitTest</TestProjectType>
+    <NuGetPackageImportStamp>
+    </NuGetPackageImportStamp>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="Microsoft.VisualStudio.TestPlatform.TestFramework, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\packages\MSTest.TestFramework.2.1.0\lib\net45\Microsoft.VisualStudio.TestPlatform.TestFramework.dll</HintPath>
+    </Reference>
+    <Reference Include="Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
+      <HintPath>..\packages\MSTest.TestFramework.2.1.0\lib\net45\Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions.dll</HintPath>
+    </Reference>
+    <Reference Include="nunit.framework, Version=3.12.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb, processorArchitecture=MSIL">
+      <HintPath>..\packages\NUnit.3.12.0\lib\net45\nunit.framework.dll</HintPath>
+    </Reference>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Builders\YellowLampRowBuilderTests.cs" />
+    <Compile Include="Extensions\IntExtensionsTests.cs" />
+    <Compile Include="Extensions\StringExtensionsTests.cs" />
+    <Compile Include="Parsers\TimeParserExtensions.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="Renderers\BerlinClockRowRendererTests.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\BerlinClock.csproj">
+      <Project>{0451204d-bf86-43e1-b560-fc9ac830b9a9}</Project>
+      <Name>BerlinClock</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <ItemGroup />
+  <Import Project="$(VSToolsPath)\TeamTest\Microsoft.TestTools.targets" Condition="Exists('$(VSToolsPath)\TeamTest\Microsoft.TestTools.targets')" />
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props'))" />
+    <Error Condition="!Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets'))" />
+    <Error Condition="!Exists('..\packages\NUnit.3.12.0\build\NUnit.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit.3.12.0\build\NUnit.props'))" />
+    <Error Condition="!Exists('..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props'))" />
+  </Target>
+  <Import Project="..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets" Condition="Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets')" />
+</Project>
\ No newline at end of file
diff --git a/BerlinClock.Tests/Builders/YellowLampRowBuilderTests.cs b/BerlinClock.Tests/Builders/YellowLampRowBuilderTests.cs
new file mode 100644
index 00000000..826bf54d
--- /dev/null
+++ b/BerlinClock.Tests/Builders/YellowLampRowBuilderTests.cs
@@ -0,0 +1,30 @@
+using BerlinClock.Builders;
+using BerlinClock.Models;
+using NUnit.Framework;
+
+namespace BerlinClock.Tests.Builders
+{
+    [TestFixture]
+    public class YellowLampRowBuilderTests
+    {
+        private YellowLampRowBuilder _sut;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _sut = new YellowLampRowBuilder();
+        }
+
+        [Test]
+        public void Build_ShouldReturnDifferentResult_WhenOddAndEvenNumbersAreGiven()
+        {
+            var oddValue = 1;
+            var evenValue = 2;
+
+            var resultForOddValue = _sut.Build(new Time(0, 0, oddValue));
+            var resultForEvenValue = _sut.Build(new Time(0, 0, evenValue));
+
+            Assert.That(resultForEvenValue, Is.Not.EqualTo(resultForOddValue));
+        }
+    }
+}
diff --git a/BerlinClock.Tests/Extensions/IntExtensionsTests.cs b/BerlinClock.Tests/Extensions/IntExtensionsTests.cs
new file mode 100644
index 00000000..1d1034f0
--- /dev/null
+++ b/BerlinClock.Tests/Extensions/IntExtensionsTests.cs
@@ -0,0 +1,29 @@
+using BerlinClock.Extensions;
+using NUnit.Framework;
+
+namespace BerlinClock.Tests.Extensions
+{
+    [TestFixture]
+    public class IntExtensionsTests
+    {
+        [Test]
+        public void IsEven_ShouldReturnTrue_WhenEvenNumberIsGiven()
+        {
+            var evenNumber = 2;
+
+            var result = evenNumber.IsEven();
+
+            Assert.That(result, Is.True);
+        }
+
+        [Test]
+        public void IsEven_ShouldReturnFalse_WhenOddNumberIsGiven()
+        {
+            var oddNumber = 3;
+
+            var result = oddNumber.IsEven();
+
+            Assert.That(result, Is.False);
+        }
+    }
+}
diff --git a/BerlinClock.Tests/Extensions/StringExtensionsTests.cs b/BerlinClock.Tests/Extensions/StringExtensionsTests.cs
new file mode 100644
index 00000000..33c3c99e
--- /dev/null
+++ b/BerlinClock.Tests/Extensions/StringExtensionsTests.cs
@@ -0,0 +1,52 @@
+using BerlinClock.Extensions;
+using NUnit.Framework;
+
+namespace BerlinClock.Tests.Extensions
+{
+    [TestFixture]
+    public class StringExtensionsTests
+    {
+        private string _value;
+        private char _valueToReplace;
+        private char _newValue;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _value = "OOOOOOO";
+            _valueToReplace = 'O';
+            _newValue = 'X';
+        }
+
+        [TestCase(null)]
+        [TestCase("")]
+        public void ReplaceEveryNthOccurence_ShouldReturnSameValue_WhenNullOrEmptyStringIsGiven(string value)
+        {
+            var result = value.ReplaceEveryNthOccurence(_valueToReplace, _newValue, 1);
+
+            Assert.That(result, Is.EqualTo(value));
+        }
+
+        [Test]
+        public void ReplaceEveryNthOccurence_ShouldNotReplaceAnyValue_WhenNValueIsOutOfRange()
+        {
+            var outOfRangeNValue = _value.Length + 1;
+
+            var result = _value.ReplaceEveryNthOccurence(_valueToReplace, _newValue, outOfRangeNValue);
+
+            Assert.That(result, Is.EqualTo(_value));
+        }
+
+        [Test]
+        public void ReplaceEveryNthOccurence_ShouldReplaceEvery3thOccurence_WhenValueOccurred()
+        {
+            var value = "OOROOOOOO";
+            var expectedValue = "OOROOXOOX";
+            var n = 3;
+
+            var result = value.ReplaceEveryNthOccurence(_valueToReplace, _newValue, n);
+
+            Assert.That(result, Is.EqualTo(expectedValue));
+        }
+    }
+}
diff --git a/BerlinClock.Tests/Parsers/TimeParserExtensions.cs b/BerlinClock.Tests/Parsers/TimeParserExtensions.cs
new file mode 100644
index 00000000..b59342d3
--- /dev/null
+++ b/BerlinClock.Tests/Parsers/TimeParserExtensions.cs
@@ -0,0 +1,47 @@
+using BerlinClock.Parsers;
+using NUnit.Framework;
+using System;
+
+namespace BerlinClock.Tests.Parsers
+{
+    [TestFixture]
+    public class TimeParserExtensions
+    {
+        private TimeParser _sut;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _sut = new TimeParser();
+        }
+
+        [Test]
+        public void Parse_ShouldThrowException_WhenGivenValueIsNull()
+        {
+            Assert.Throws<Exception>(() => _sut.Parse(null));
+        }
+
+        [Test]
+        public void Parse_ShouldThrowException_WhenWrongTimeFormatIsGiven()
+        {
+            var wrongTime = "123400";
+
+            Assert.Throws<Exception>(() => _sut.Parse(wrongTime));
+        }
+
+        [Test]
+        public void Parse_ShouldCreateCorrectInstance_WhenCorrectTimeIsGiven()
+        {
+            var hour = 12;
+            var minute = 45;
+            var second = 30;
+            var timeValue = $"{hour}:{minute}:{second}";
+
+            var result = _sut.Parse(timeValue);
+
+            Assert.That(result.Hour, Is.EqualTo(hour));
+            Assert.That(result.Minute, Is.EqualTo(minute));
+            Assert.That(result.Second, Is.EqualTo(second));
+        }
+    }
+}
diff --git a/BerlinClock.Tests/Properties/AssemblyInfo.cs b/BerlinClock.Tests/Properties/AssemblyInfo.cs
new file mode 100644
index 00000000..0a3129db
--- /dev/null
+++ b/BerlinClock.Tests/Properties/AssemblyInfo.cs
@@ -0,0 +1,20 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+[assembly: AssemblyTitle("BerlinClock.Tests")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("BerlinClock.Tests")]
+[assembly: AssemblyCopyright("Copyright ©  2020")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+[assembly: ComVisible(false)]
+
+[assembly: Guid("74f9d721-6839-4776-97c9-718145ced3d0")]
+
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]
diff --git a/BerlinClock.Tests/Renderers/BerlinClockRowRendererTests.cs b/BerlinClock.Tests/Renderers/BerlinClockRowRendererTests.cs
new file mode 100644
index 00000000..77f76427
--- /dev/null
+++ b/BerlinClock.Tests/Renderers/BerlinClockRowRendererTests.cs
@@ -0,0 +1,79 @@
+using BerlinClock.Models;
+using BerlinClock.Renderers;
+using NUnit.Framework;
+using System;
+
+namespace BerlinClock.Tests.Renderers
+{
+    [TestFixture]
+    public class BerlinClockRowRendererTests
+    {
+        private BerlinClockRowRenderer _sut;
+
+        [SetUp]
+        public void SetUp()
+        {
+            _sut = new BerlinClockRowRenderer();
+        }
+
+        [Test]
+        public void Render_ShouldNotModifyResult_WhenAdditionalFormattingIsNull()
+        {
+            var expectedValue = "XO";
+            var request = new BerlinClockRendererRequest
+            {
+                AdditionalFormatting = null,
+                TurnedOnLampSign = 'X',
+                AmountOfTurnedOnLamps = 1,
+                AmountOfTurnedOffLamps = 1
+            };
+
+            var result = _sut.Render(request);
+
+            Assert.That(result, Is.EqualTo(expectedValue));
+        }
+
+        [Test]
+        public void Render_ShouldModifyResult_WhenAdditionalFormattingIsGiven()
+        {
+            var expectedValue = "TEST";
+            var request = new BerlinClockRendererRequest
+            {
+                AdditionalFormatting = (row) => expectedValue,
+                TurnedOnLampSign = 'X',
+                AmountOfTurnedOnLamps = 1,
+                AmountOfTurnedOffLamps = 1
+            };
+
+            var result = _sut.Render(request);
+
+            Assert.That(result, Is.EqualTo(expectedValue));
+        }
+        
+        [Test]
+        public void Render_ShouldThrowException_WhenNegativeTurnedOnLampsValueIsGiven()
+        {
+            var request = new BerlinClockRendererRequest
+            {
+                TurnedOnLampSign = 'X',
+                AmountOfTurnedOnLamps = -1,
+                AmountOfTurnedOffLamps = 1
+            };
+
+            Assert.Throws<Exception>(() => _sut.Render(request));
+        }
+
+        [Test]
+        public void Render_ShouldThrowException_WhenNegativeTurnedOffLampsValueIsGiven()
+        {
+            var request = new BerlinClockRendererRequest
+            {
+                TurnedOnLampSign = 'X',
+                AmountOfTurnedOnLamps = 1,
+                AmountOfTurnedOffLamps = -1
+            };
+
+            Assert.Throws<Exception>(() => _sut.Render(request));
+        }
+    }
+}
diff --git a/BerlinClock.Tests/packages.config b/BerlinClock.Tests/packages.config
new file mode 100644
index 00000000..929338d9
--- /dev/null
+++ b/BerlinClock.Tests/packages.config
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="NUnit" version="3.12.0" targetFramework="net45" />
+  <package id="NUnit3TestAdapter" version="3.16.1" targetFramework="net45" developmentDependency="true" />
+</packages>
\ No newline at end of file
diff --git a/BerlinClock.csproj b/BerlinClock.csproj
index 514b738f..b7152573 100644
--- a/BerlinClock.csproj
+++ b/BerlinClock.csproj
@@ -54,6 +54,7 @@
     <Compile Include="Builders\BerlinClockRowsBuilderBase.cs" />
     <Compile Include="Builders\HourRowsBuilder.cs" />
     <Compile Include="Builders\MinuteRowsBuilder.cs" />
+    <Compile Include="Builders\YellowLampRowBuilder.cs" />
     <Compile Include="Extensions\IntExtensions.cs" />
     <Compile Include="Extensions\StringExtensions.cs" />
     <Compile Include="Models\BerlinClockEntity.cs" />
diff --git a/BerlinClock.sln b/BerlinClock.sln
index 082911a2..1114bf1f 100644
--- a/BerlinClock.sln
+++ b/BerlinClock.sln
@@ -5,6 +5,8 @@ VisualStudioVersion = 12.0.21005.1
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "BerlinClock", "BerlinClock.csproj", "{0451204D-BF86-43E1-B560-FC9AC830B9A9}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "BerlinClock.Tests", "BerlinClock.Tests\BerlinClock.Tests.csproj", "{74F9D721-6839-4776-97C9-718145CED3D0}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -15,6 +17,10 @@ Global
 		{0451204D-BF86-43E1-B560-FC9AC830B9A9}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{0451204D-BF86-43E1-B560-FC9AC830B9A9}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{0451204D-BF86-43E1-B560-FC9AC830B9A9}.Release|Any CPU.Build.0 = Release|Any CPU
+		{74F9D721-6839-4776-97C9-718145CED3D0}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{74F9D721-6839-4776-97C9-718145CED3D0}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{74F9D721-6839-4776-97C9-718145CED3D0}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{74F9D721-6839-4776-97C9-718145CED3D0}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/Builders/BerlinClockEntityBuilder.cs b/Builders/BerlinClockEntityBuilder.cs
index 7466dfc5..95abd977 100644
--- a/Builders/BerlinClockEntityBuilder.cs
+++ b/Builders/BerlinClockEntityBuilder.cs
@@ -1,5 +1,4 @@
-using BerlinClock.Extensions;
-using BerlinClock.Models;
+using BerlinClock.Models;
 
 namespace BerlinClock.Builders
 {
@@ -12,26 +11,31 @@ public class BerlinClockEntityBuilder : IBerlinClockEntityBuilder
     {
         private readonly IHourRowsBuilder _hourRowsBuilder;
         private readonly IMinuteRowsBuilder _minuteRowsBuilder;
+        private readonly IYellowLampRowBuilder _yellowLampRowBuilder;
 
-        public BerlinClockEntityBuilder() : this(new HourRowsBuilder(), new MinuteRowsBuilder())
+        public BerlinClockEntityBuilder() : this(new HourRowsBuilder(), new MinuteRowsBuilder(),
+            new YellowLampRowBuilder())
         {
 
         }
 
-        public BerlinClockEntityBuilder(IHourRowsBuilder hourRowsBuilder, IMinuteRowsBuilder minuteRowsBuilder)
+        public BerlinClockEntityBuilder(IHourRowsBuilder hourRowsBuilder, IMinuteRowsBuilder minuteRowsBuilder,
+            IYellowLampRowBuilder yellowLampRowBuilder)
         {
             _hourRowsBuilder = hourRowsBuilder;
             _minuteRowsBuilder = minuteRowsBuilder;
+            _yellowLampRowBuilder = yellowLampRowBuilder;
         }
 
         public BerlinClockEntity Build(Time time)
         {
             var hourRows = _hourRowsBuilder.Build(time);
             var minuteRows = _minuteRowsBuilder.Build(time);
+            var yellowLampRow = _yellowLampRowBuilder.Build(time);
 
             return new BerlinClockEntity
             {
-                YellowLampSign = time.Second.IsEven() ? 'Y' : 'O',
+                YellowLampRow = yellowLampRow,
                 FirstHoursRow = hourRows.FirstRow,
                 SecondHoursRow = hourRows.SecondRow,
                 FirstMinutesRow = minuteRows.FirstRow,
diff --git a/Builders/BerlinClockRowsBuilderBase.cs b/Builders/BerlinClockRowsBuilderBase.cs
index 11e8a63e..e9b04fb8 100644
--- a/Builders/BerlinClockRowsBuilderBase.cs
+++ b/Builders/BerlinClockRowsBuilderBase.cs
@@ -12,12 +12,11 @@ public interface IBerlinClockRowsBuilder
     public abstract class BerlinClockRowsBuilderBase : IBerlinClockRowsBuilder
     {
         protected abstract int FirstRowLampsAmount { get; }
-        protected abstract int FirstRowLampsValue { get; }
+        protected abstract int FirstRowLampValue { get; }
         protected abstract int SecondRowLampsAmount { get; }
-        protected abstract int SecondRowLampsValue { get; }
+        protected abstract int SecondRowLampValue { get; }
         protected abstract char TurnedOnLampSign { get; }
         protected virtual Func<string, string> FirstRowAdditionalFormatting { get; }
-        protected virtual Func<string, string> SecondRowAdditionalFormatting { get; }
 
         private readonly IBerlinClockRowRenderer _berlinClockRowRenderer;
 
@@ -29,10 +28,10 @@ public BerlinClockRowsBuilderBase(IBerlinClockRowRenderer berlinClockRowRenderer
         public BerlinClockRows Build(Time time)
         {
             var timePart = ExtractTimePart(time);
-            var amountOfTurnedOnLampsAtFirstRow = (int)timePart / FirstRowLampsValue;
+            var amountOfTurnedOnLampsAtFirstRow = timePart / FirstRowLampValue;
             var amountOfTurnedOffLampsAtFirstRow = FirstRowLampsAmount - amountOfTurnedOnLampsAtFirstRow;
 
-            var amountOfTurnedOnLampsAtSecondRow = (int)(timePart - amountOfTurnedOnLampsAtFirstRow * FirstRowLampsValue) / SecondRowLampsValue;
+            var amountOfTurnedOnLampsAtSecondRow = (timePart - (amountOfTurnedOnLampsAtFirstRow * FirstRowLampValue)) / SecondRowLampValue;
             var amountOfTurnedOffLampsAtSecondRow = SecondRowLampsAmount - amountOfTurnedOnLampsAtSecondRow;
 
             return new BerlinClockRows
@@ -48,8 +47,7 @@ public BerlinClockRows Build(Time time)
                 {
                     AmountOfTurnedOnLamps = amountOfTurnedOnLampsAtSecondRow,
                     AmountOfTurnedOffLamps = amountOfTurnedOffLampsAtSecondRow,
-                    TurnedOnLampSign = TurnedOnLampSign,
-                    AdditionalFormatting = SecondRowAdditionalFormatting
+                    TurnedOnLampSign = TurnedOnLampSign
                 })
             };
         }
diff --git a/Builders/HourRowsBuilder.cs b/Builders/HourRowsBuilder.cs
index ec2fdeb1..aaae68b5 100644
--- a/Builders/HourRowsBuilder.cs
+++ b/Builders/HourRowsBuilder.cs
@@ -20,9 +20,9 @@ public HourRowsBuilder(IBerlinClockRowRenderer berlinClockRowRenderer) : base(be
 
         protected override char TurnedOnLampSign => 'R';
         protected override int FirstRowLampsAmount => 4;
-        protected override int FirstRowLampsValue => 5;
+        protected override int FirstRowLampValue => 5;
         protected override int SecondRowLampsAmount => 4;
-        protected override int SecondRowLampsValue => 1;
+        protected override int SecondRowLampValue => 1;
         protected override int ExtractTimePart(Time time)
         {
             return time.Hour;
diff --git a/Builders/MinuteRowsBuilder.cs b/Builders/MinuteRowsBuilder.cs
index 670874c7..62b49da2 100644
--- a/Builders/MinuteRowsBuilder.cs
+++ b/Builders/MinuteRowsBuilder.cs
@@ -24,9 +24,9 @@ public MinuteRowsBuilder(IBerlinClockRowRenderer berlinClockRowRenderer) : base(
         }
 
         protected override int FirstRowLampsAmount => 11;
-        protected override int FirstRowLampsValue => 5;
+        protected override int FirstRowLampValue => 5;
         protected override int SecondRowLampsAmount => 4;
-        protected override int SecondRowLampsValue => 1;
+        protected override int SecondRowLampValue => 1;
         protected override char TurnedOnLampSign => 'Y';
         protected override int ExtractTimePart(Time time)
         {
diff --git a/Builders/YellowLampRowBuilder.cs b/Builders/YellowLampRowBuilder.cs
new file mode 100644
index 00000000..96c2d213
--- /dev/null
+++ b/Builders/YellowLampRowBuilder.cs
@@ -0,0 +1,23 @@
+using BerlinClock.Extensions;
+using BerlinClock.Models;
+
+namespace BerlinClock.Builders
+{
+    public interface IYellowLampRowBuilder
+    {
+        char Build(Time time);
+    }
+
+    public class YellowLampRowBuilder : IYellowLampRowBuilder
+    {
+        private const char LampOnSign = 'Y';
+        private const char LampOffSign = 'O';
+
+        public char Build(Time time)
+        {
+            return time.Second.IsEven() 
+                ? LampOnSign 
+                : LampOffSign;
+        }
+    }
+}
diff --git a/Extensions/StringExtensions.cs b/Extensions/StringExtensions.cs
index 606a4334..61a85a30 100644
--- a/Extensions/StringExtensions.cs
+++ b/Extensions/StringExtensions.cs
@@ -7,6 +7,9 @@ public static class StringExtensions
     {
         public static string ReplaceEveryNthOccurence(this string value, char valueToReplace, char newValue, int n)
         {
+            if (string.IsNullOrWhiteSpace(value))
+                return value;
+
             var chars = value.Select((val, index) => 
                 val == valueToReplace && (index + 1) % n == 0 ? newValue : val);
 
diff --git a/Models/BerlinClockEntity.cs b/Models/BerlinClockEntity.cs
index a9d6e143..22316206 100644
--- a/Models/BerlinClockEntity.cs
+++ b/Models/BerlinClockEntity.cs
@@ -4,7 +4,7 @@ namespace BerlinClock.Models
 {
     public class BerlinClockEntity
     {
-        public char YellowLampSign { get; set; }
+        public char YellowLampRow { get; set; }
         public string FirstHoursRow { get; set; }
         public string SecondHoursRow { get; set; }
         public string FirstMinutesRow { get; set; }
@@ -12,7 +12,7 @@ public class BerlinClockEntity
 
         public override string ToString()
         {               
-            return string.Join(Environment.NewLine, YellowLampSign, 
+            return string.Join(Environment.NewLine, YellowLampRow, 
                 FirstHoursRow, SecondHoursRow, 
                 FirstMinutesRow, SecondMinutesRow);
         }
diff --git a/Parsers/TimeParser.cs b/Parsers/TimeParser.cs
index 184cbd4a..924a05fa 100644
--- a/Parsers/TimeParser.cs
+++ b/Parsers/TimeParser.cs
@@ -10,9 +10,13 @@ public interface ITimeParser
 
     public class TimeParser : ITimeParser
     {
+        private const char Separator = ':';
         public Time Parse(string time)
         {
-            var timeParts = time.Split(':');
+            if (time == null)
+                throw new Exception("Time must not be null");
+
+            var timeParts = time.Split(Separator);
             if (timeParts.Length != 3)
                 throw new Exception("Wrong time format");
 
diff --git a/Renderers/BerlinClockRowRenderer.cs b/Renderers/BerlinClockRowRenderer.cs
index c01afd43..d6c2395e 100644
--- a/Renderers/BerlinClockRowRenderer.cs
+++ b/Renderers/BerlinClockRowRenderer.cs
@@ -1,4 +1,5 @@
 using BerlinClock.Models;
+using System;
 using System.Text;
 
 namespace BerlinClock.Renderers
@@ -14,6 +15,9 @@ public class BerlinClockRowRenderer : IBerlinClockRowRenderer
 
         public string Render(BerlinClockRendererRequest request)
         {
+            if (request.AmountOfTurnedOffLamps < 0 || request.AmountOfTurnedOnLamps < 0)
+                throw new Exception("Cannot render negative values");
+
             var stringBuilder = new StringBuilder();
             stringBuilder.Append(request.TurnedOnLampSign, request.AmountOfTurnedOnLamps);
             stringBuilder.Append(TurnedOffLampSign, request.AmountOfTurnedOffLamps);

From 28d4be868ef9f37688ef64b9595b5817c91e4405 Mon Sep 17 00:00:00 2001
From: rwiktorek <rafalwiktorek71@gmail.com>
Date: Tue, 5 May 2020 11:34:27 +0200
Subject: [PATCH 3/4] we dont need references to mstests adapter

---
 BerlinClock.Tests/BerlinClock.Tests.csproj | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/BerlinClock.Tests/BerlinClock.Tests.csproj b/BerlinClock.Tests/BerlinClock.Tests.csproj
index 8e547829..caebf629 100644
--- a/BerlinClock.Tests/BerlinClock.Tests.csproj
+++ b/BerlinClock.Tests/BerlinClock.Tests.csproj
@@ -2,7 +2,6 @@
 <Project ToolsVersion="15.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props" Condition="Exists('..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props')" />
   <Import Project="..\packages\NUnit.3.12.0\build\NUnit.props" Condition="Exists('..\packages\NUnit.3.12.0\build\NUnit.props')" />
-  <Import Project="..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props" Condition="Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props')" />
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
@@ -41,12 +40,6 @@
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="Microsoft.VisualStudio.TestPlatform.TestFramework, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\MSTest.TestFramework.2.1.0\lib\net45\Microsoft.VisualStudio.TestPlatform.TestFramework.dll</HintPath>
-    </Reference>
-    <Reference Include="Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions, Version=14.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <HintPath>..\packages\MSTest.TestFramework.2.1.0\lib\net45\Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions.dll</HintPath>
-    </Reference>
     <Reference Include="nunit.framework, Version=3.12.0.0, Culture=neutral, PublicKeyToken=2638cd05610744eb, processorArchitecture=MSIL">
       <HintPath>..\packages\NUnit.3.12.0\lib\net45\nunit.framework.dll</HintPath>
     </Reference>
@@ -77,10 +70,7 @@
     <PropertyGroup>
       <ErrorText>This project references NuGet package(s) that are missing on this computer. Use NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105. The missing file is {0}.</ErrorText>
     </PropertyGroup>
-    <Error Condition="!Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.props'))" />
-    <Error Condition="!Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets'))" />
     <Error Condition="!Exists('..\packages\NUnit.3.12.0\build\NUnit.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit.3.12.0\build\NUnit.props'))" />
     <Error Condition="!Exists('..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\NUnit3TestAdapter.3.16.1\build\net35\NUnit3TestAdapter.props'))" />
   </Target>
-  <Import Project="..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets" Condition="Exists('..\packages\MSTest.TestAdapter.2.1.0\build\net45\MSTest.TestAdapter.targets')" />
 </Project>
\ No newline at end of file

From 356af0fea171d1b4e11c024f8c6d0212b66fb02d Mon Sep 17 00:00:00 2001
From: rwiktorek <rafalwiktorek71@gmail.com>
Date: Tue, 5 May 2020 11:39:35 +0200
Subject: [PATCH 4/4] remove empty tag

---
 BerlinClock.csproj | 1 -
 1 file changed, 1 deletion(-)

diff --git a/BerlinClock.csproj b/BerlinClock.csproj
index b7152573..2a9b8c49 100644
--- a/BerlinClock.csproj
+++ b/BerlinClock.csproj
@@ -82,7 +82,6 @@
   <ItemGroup>
     <Service Include="{82A7F48D-3B50-4B1E-B82E-3ADA8210C358}" />
   </ItemGroup>
-  <ItemGroup />
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.